Production of alpha-nitronaphthalene-beta-sulphonic acids



RALPH A. NELSON, OF BUFFALO,

CHEMICAL 00., INC., 01 NEW YORK,

' No Drawing. Application filed Kay s,

This invention relates to the roduction of alplia-nitronaphthalene-beta su phonic acids from naphthalene. These acids, or the reaction mixture containing them me 'be re- 5 duced to form the so-called dleves acids. These acids consist mainly of .a mixture of the 1.6- and 1.7-naphthylamine-sulphonic' acids. Some small amount of the 1.3-naphthylamine-sulphonic'acid may also be present, but the amount is relatively small.

According to the present invention, naphthalene is subjected to sulphonation at an elevated temperature and t e product of sulphonation, containing the naphthalene-beta- 16 sul honic acids, is subjected to nitration wit out isolation from the excess sulphuricacid, so that the same excess sulphuric acid assists in both the sul honation and nitration operations. The a pha-nitro derivatives 20 thus produced may then be subjected to reduction to convert the nitro derivatives into amido derivatives. The amido derivatives thus produced can be isolated, either in the form of, the free acids, or in the form of salts thereof. The sulphonation of the na the production of the nap thalene-betamono-sulphonic acids, is carried out at an elevated temperature, by melting the naph- 8 thalene, heating it to a tem erature of around 140 to 166 (3., and adding the sul-' phuric acid thereto, so that the sul honation'takes place rapidly and at an e evated tem erature and Wlth' the direct production 85 of t e beta-sulphonic acids. Durmg the ad- ,dition of the sulphuric acid, the mixture is agitated at such a rate as to prevent the formation of two segarate layers. The sulphonation can be e acted with 66 B. (i. e.,

40 about 93.2%) sulphuric acid, but is more advantageously eifected by the use of 100% sul huric acid. a

he sulphonation product will contain the large excess of concentrated sulphuric acid required to complete the sulphonation; The sulphonic acids are not separated from. this excess sulphuric acid, but the sulphona-ution product, still containing the excess sula:

phuric acid, isutilized directly for them nation, by, theaddition thereto of the nitrating agent together with such further amounts of sulphuric acid as maybe neces sary. The excess sulphuric acid from the sulphonation is thus made available in the nitration, effecting an importanteconomy hthalene, for

N. Y., a. CORPORATION or naw Yoa'x.

PRODUCTION OI ALPHA-NITRONAPHTHALENE-NETA-QULrHONHJ ACIDS.

1920. Serial No. states.

NEW YORK, ASSIGNOB '10 NATIONAL ANILINE &

in the amount of sulphuric acid required to v be separately added for the nitration, while the use of the hot sulphonation product is further advantageous in economizing in the amount of heat required for heating the nitrating mixture to the nitrating temperature. The nitration is effected at a suitable temperature of about '45 to with gradual addition of the nitrating agent. After Collipletion of the nitration, the productis neutralized with lime, the precipitated gy sum or calcium sulphate filtered'while stil hot. If it is desired to'produceCleves acid from the alpha nitronaphthalene beta-sulphonid acid of the present invention, the filtrate while still hot, is subjected to reduction, pret erably by means of acetic acid and powdered iron, with such further heating as may be necessary. The reduction product may be separated from the accompanying iron oxide or iron compound and may be suitably treat ed for the isolation of alpha-naphthylaminebeta-sulphonic acid, either as such, or in the form of'their sodium or other salts.

The invention will be further illustrated in connection with the production of Cleves acid by the following specific example, the parts being by weight:

Sulph0mtion.325 parts of naphthalene are introduced into a sulphonation kettle equipped with an agitator, preferably of the propfller type closely fitting the bottom period of about 15 minutes. The heating is continued-during the addition of the acid to prevent any appreciable drop in tem erature, heating is t en discontinued, an Y the a itation continued for a further period of 11a at 10 .minutes the temperature being maintained around :plfetion of the sulphonation, the sulphonation transferred to the nitrating kettle, which may be efiected by. blowing the sulphonation product, by means of air ressure, through preheated pipes. The sulphonation product is then agitated while it slowly cools to a temperature of about to 0.,

165 C. At the comproduct, while still in a heated state, is 1105 .The sulphonation product is not treated for the separation of the naphthalene-sulphonic acids from'the excesssulphuric acid, but this excess sulphuric acid is left in the mixture and a further addition is made of about 470 pounds of sulphuric acid of 66 B. which may conveniently be run into the sulphonating kettle and then transferred to the nitratinglkettle when the sulphonationproduct has cooled to the temperature above indicated, i. e., about 85 to 90. The whole mixture is then preferably cooled with continued agitation to about 55 prior to the nitration.

Nitratz'0n.To the sulphonation product with added sulphuric acid, produced as above described, there is added gradually about 300 pounds of 56% nitric acid and the nitration is carried out at a temperature between +15 and 60, with active cooling. The rate of addition of the acid depends upon the cooling effect available, but may require from 4 to 6 hours or longer. The temperature is preferably kept as close as possible to 55 C. and for best results should not rise above 60 C. After the addition ofthe nitric acid is completed, agitation is continued for a further period ofabout 30 to minutes to allow completion of the nitration, with further heating if necessary to maintain the temperature. When the nitration is completed, the product is transferred to the neutralizing vat where the excess acid is neutralized with lime.

N eutmlz'e ationr The nitration. product is introduced into about 9500 pounds of wash water from revious neutralization-operations. The mixture is heated to about 60 C. by the injection of steam "and slaked lime is then added equivalent to about 600 pounds the gypsum is returned to of unslaked lime, while agitatin the mixture, until it; is neutral or slight y alkaline in reaction. 'It is their filteredwhile still hot to remove the gypsum, for example, by forcing it through a filter press. The filtrate is collected for the subsequent reduction together with the first washings. The wash water resulting from subseqpent washing of t e neutralization vat for use in subsequent reductions.

Reduction.Thefiltrate containing the nitro-sulphonic acids, is heated to about to C..before reduction is started. About 15 to 20 pounds of'80% acetic acidis then 'added and about 300 pounds of powdered iron and the temperature is maintained atabout 95 to 100 C. during the reduction.-

The progress is 'followed byspot testing on filter'paper. When the reaction is complete, the wet rrn, at the outside of the spot 'is nearly color ess when the spot is made, and,

as the spot dries, the outside ring turnsto a purplish gray. After the reductlon is-con- 7 tinned for some time, it is necessary to add iron about. 400 to 450 pounds. The complete reduction may take as much as 6 t0 8 hours or more for its com letion. When finished the iron oxide is alibwed to settle, the liquor is drawn ofl", the iron oxide again agitated with a little water and again allowed to settle and the wash water-drawn off and admixed with the-reduction liquors which are then. filtered through a suitable filter press. The washing can be repeated with hot water until the solution is quite clear and red in color. The reduction liquors are concentrated to about 7-8 B. while. I

hot and are again subgected' to filtration and.

the sludge Washed.

The hot liquors from the filter press are immediately acidified with 20 B. hydrochloric acid until a strong acid reaction on Congo red paper is'obtained, about 300 pounds of acid being required. Agitation is continued for about 6 to 8 hours to prevent the formation of a crust of heavy crystals on the bottom of the apparatus and the liquor is permitted-tostand for a further period of time which may amount to as much as 2 days, after which the Cleves acid is filtered remove the mother liquor. Theproduct is somewhat soluble in water so that continuous washing is objectionable, but the washingcan be effected by displacing the mother. liquor with-fresh water and allowing the fresh water to stand for a short time before forcin .it out of the press, and repeating the was ing in this way until the mother liquor is removed. The product obtained in the filter is then further dried and gives the Cleves acid in a dried and isolated state.

The'process can be carried out 111 a somewhat more advantageous manner by usm 100% sulphuric acid instead of 66 B. aci

(about 94%). By making use of 100% sulphuric acid it is possible to use consider-- ably less total sul huric acid' in .both the sulphonation and t e nitration, with result ing economy in both operations. So also, I

less lime is required to neutralize the nitration liquors and less gypsum is formed so that the filtering capacity required is re- .duced or, with a given filtering capacity, increased production per workin unit is permitted. The practice ofthe invention making use'of 100% sulphuric acid will be further illustrated by the following spea cific exam le which also illustrates the pro- 1 duction o Gleves acid from the nitronaphthalene-sulphonic acid prepared by the present invention:

Sulphonation.500 ounds of naphthalene A are melted in the su phonating kettle and heated to a temperature of about C. Sulphuric acid of 100% strengthis thenthrough a suitable filter press and washed to 5' the temperature gradually rising to' about 160 to 164 C.I After the acid is all added, agitation is continued for a further period of about 5 to"-f10 minutes and the'sulphonwtion roduct is then transferred to the nitra-v tion ettle.

Nitratz'om-The sul cooled, withcontinue agitation, and when near their solidific' tion point (70 to 80 C.) there is added gradually about .310 pounds of 100% sulphuric acid, which acid is added just fast enough to keep the sulphonation product fluid as it is being cooled to about 45 to 50 C. The nitration is then effected by the gradual addition of about 330 pounds of 67 nitric acid (42 B.), and with energetic cooling, while maintaining the'temperature at 45 to 60 C. until the addition of the nitric acid is comipleted, which may require as much as 6 to 10 hours or more, depending upon the rate of cooling, The agitation is continued for a further period of about'half an hour at the same temperature and'the nitration product is then transferred to the neutral ization vat where it is diluted with about 10,000, pounds of water, the mixture heated,

and sufiicient lime added for neutralization.

- The neutralized liquor is filtered hot, the

-%ypsum washed -with hot water, and the trate and first washings used for subsequent reduction, while, subsequent washings are returned to the neutralization tank for admixture with the next nitration product.

Reduction-The reduction of the neutralized' liquor is carried out at around 90 to 100 in such a way that the liquors are concentrated during the reduction. About 30 pounds'of acetic acid of 80% strength and 500 pounds of iron are added, and the reduction continued for-a suflicient period of time, with agitation and generally heating, a further addition of 5 pounds of acetic acid and pounds of iron being added to insure completion of the reduction. The progress of the reaction is followed by the spot test on paper." The complete reduction may require as much as 10 to 12 hours. After completion, the reduction product is allowed to settle, the liquor drawn off, the

' sludge washed-by agitatlng with water and again allowed to settle and drawing off the wash water; The liquors drawn oii are filtered hot and the filtrate and first Washings concentrated, to about 78 B. and

again filter hot. The hot filtrate from the press, at a temperature of'about 55 to (3., is treated with hydrochloric acid until it becomesdefinitely' acid to Congo red paper,

{about 400 pounds of 20 B. acid being required. Care should be taken that the acid .test due to the Cleves-acids themselves is not mi taken for the acidity due to hydrohonation liquors are.

agitated and chloric acid which turns the. Congo red paer a deep blue. After the acidification, the atch is allowed to stand for a period of 2 to 3 days separation of the Cleves acids, which are then separated by filtering and intermmitinthe manner above described.

In case it is desired to separate acids in the form of their sodium salts, this can be advantageously efie'cted by diluting the reduction liquors, making them definitely alkaline with soda at a temperature of about 95 C., filtering off the precipitate, concentrating the mother li uor and separating the'sodium salts by t e addition of suflicient common salt.

.From the foregoing description it will be men that the improved process of the present invention involves the 'sulphonation of naphthalene at an elevated temperature and in such a way as to produce a hi h yield of the beta-sulphonic acids, andtlie subsequent nitration of the sulphonic acids without isolation thereof from the sulphonation. product,so that the excess sulphuric with agitation in order to efiect tent washing ofthe filtrate with cold water the Cleves I acid used in the sill honation is present in molten naphthalene, the reaction taking place at a temperature around 140-166 (3., add ing further amounts of sulphuric acid to the sulphonation, product still containing the excess sulphuric acid from the sulphonat-ion, and subjecting the resulting mixture to. nitration by treatment with a nitrating agent.

ation by the action of sulphuric acid uponv 2.-The method of producing alpha-nitronaphthalene-beta-sulphonic acids, which comprises subjecting naphthalene to sulphonation by the addition of sulphuric acid of 100% strength to molten naphthalene,

the reaction taking place at, a temperature around 140to 166 C.,'and subjecting the sulphonation product, while still admixed with the excess sulphuric acid from the sulphonation, to nitration by treatment with a nitrating agent.

3. The'method of producing alpha-nitronaphthalene-betasulphonic acids, which comprises subjecting naphthalene to sulphonation by the action of sulphuric acid of 100% strength upon molten naphthalene, the reaction; taking place at a temperature around 140 to 166 (1., adding further amounts of sulphuric acid of 100% strength to the sulphonation product still-containing nitration by treatment with a nitrating agent.

' 4'. The method of producing alpha-nitro-.

naphthalene-beta-sulphonic acids, which comprises subjecting naphthalene to sulphonation by the action of sulphuric acid of 100% strength upon molten naphthalene, the reaction taking place at a temperature around 140 't0 166 0., adding further amounts of sulphuric acid to the sulphonation product still containing the excess sulphuric acid from the sulphonation, and subjecting the resulting mixture to nitration by treatment with a nitrating agent.

5. The method of'producing alpha-nitronaphthalene-beta-sulphonic acids, which com rises nitratin with the addition of furt er amounts 0 sulphuric acid, the sulphonation product obtained by subjecting molten naphthalene to the action of sulphuric acid, the reaction being carried out at a temperature around 140-166 (l, and from which product the excess of sulphuric acid from the sulphonation has not been removed.

6. The method of producing alpha-nitro naphthalene-beta-sulphonic acids, which comprises subjecting naphthalene to the action of an excess of sulphuric acid to effect sulphonation, the reaction taking place at a temperature of about 140 to 166 0., subsequently efiecting nitration bythe addition of a nitrating agent to the mixture of the sulphonation product and the excess sulphuric acid to which a further amount of sulphuric acid has been added, and carr ing out the nitration at a temperature of 2. out to C.

7. A method for producingv alpha-nitronaphthalene-beta-sulphonic acids, which comprises subjectin naphthalene to the action of an excess 0 sulphuric acid to effect sulphonation, the reaction taking place at a temperature of about 140 to 166 0., subsequently effecting nitration by the addition of a nitrating agent to the mixture'of the sulphonation product and the excess sulphuric acid to which a further amount of sulphuric acid has been added, and carrying out the nitration at the temperature of approximately 55 to.60- C.

'8. The method of roducing alpha-nitronaphthalene-beta-sulp'onic acids, which comprises subjectin one part of naphtha.- leneltd the action 0 about 1.2 parts of sulphuric acid of 100% strength for a. period of about 20 to 25 minutes, the reaction taking place at a temperature of about 140 to 166 C., cooling the mixture to about to C. and gradually adding about 0.6 parts sulphuric acid of strength as the mixture further cools to about 4550 C., and

subsequently subjecting the resulting mix ture to nitrationbyi adding thereto about 0.65 parts of nitric acid having a strength of about 67.5%, the temperature of the mixture during nitration ueing maintained at about 4560 C.

9. The method of producing alpha-nitronaphthalene-beta-sulph onic "acids, which comprises subjecting naphthalene to sulphonation by the addition of sulphuric acid of about 93.2'to 100% strength to molten naphthalene, the reaction taking place at a. temperature around to 166 0., and subjecting the sulphonation product, While still admixed with the excess sulphuric acid from the sulphonation, to nitration by treatment with a nitrating agent.

In testimony whereof I affix my signature.

RALPH A. NELSON. 

